1. Field of the Invention
The present invention relates to a data processing apparatus, a content displaying method, and a non-transitory computer-readable recording medium encoded with a browsing program. More particularly, the present invention relates to a data processing apparatus provided with a touch panel, a content displaying method performed by the data processing apparatus, and a non-transitory computer-readable recording medium encoded with a browsing program for causing a computer to perform the content displaying method.
2. Description of the Related Art
Some recent data processing apparatuses, typified by multi-function peripherals (MFPs), are provided with a touch panel as a user interface. The touch panel can detect a user operation of moving a position designated by the user. During the user operation of moving the designated position, however, the content of the designation changes in accordance with the movement of the position designated by the user. For example, a user designation of zooming in on an image includes a pinch-out operation in which two different locations are designated simultaneously with two fingers and the spacing between the two fingers is increased over time. When a scaling factor is determined in accordance with the spacing between the two fingers in the pinch-out operation, the scaling factor will vary while the user is inputting the pinch-out operation. Therefore, in the process of zooming in on an image, a new image needs to be displayed each time the scaling factor is changed.
U.S. Pat. No. 7,009,626 describes the following technique. For changing a size of an image of source data which is being displayed, the size of the image being displayed is changed, and the image being displayed is replaced with an image which has been changed in size. Thereafter, an image of the changed size is generated from the source data, and the image being displayed is replaced with the image generated from the source data.
Although the conventional technique can display the image of the changed size quickly when the entire image is being displayed, it cannot quickly display the image of the changed size when only a part of the image is being displayed. More specifically, in the case of reducing the size of the image being displayed, an area not being displayed will have to be displayed. In order to display the area not being displayed, an image of the size corresponding to the changed size will have to be generated from the source data. Therefore, it takes time to display the image of the changed size.